I think I'm the opposite. I find a 5- or 6-string easier thanks in part to the extra range within a single position (not necessarily extra low or high notes available). If I'm playing by ear, I can just land on the right notes more readily with the extra strings. Now, whether or not I can tell you right away what those notes are is another matter entirely. But the repeating cross-string interval patterns are more evident to me on a 5- or 6-string, which makes it easier to turn off my brain and just play.